This invention relates to a thermally responsive valve assembly and more particularly to such a multi-port valve assembly which is specifically adapted to be positioned in heat-transfer relation with an object (e.g. an automobile engine block) to switch the multiport valve system upon increase or decrease in temperature.
The multiple port, multiple temperature valve assembly of this invention is particularly adapted for use in automotive emission control systems to vent or block a vacuum system upon the engine reaching various desired operating temperatures. Multiple port wax actuated valves are currently used for automotive emission control systems. These valves consist of valve means actuated by a volume change of wax upon reaching a predetermined temperature. These valves, however, are only actuatable at one temperature and eventually are subject to loss of wax and consequently a shift of operating temperature due to the high pressure buildup.
It is an object of this invention to provide a thermally responsive valve assembly that is actuatable at more than one temperature. It is yet another object of this invention to provide a thermally responsive valve assembly which is of compact size and to which a plurality of tubes or the like may be readily connected to ports entering the valve assembly. It is still another object of this invention to provide a multi-port, multi-temperature thermally responsive valve which is economical to manufacture, easy to install and reliable in operation. Other objects and features of this invention will be in part apparent and in part pointed out hereinafter.
Briefly, a multi-port, multi-temperature thermally responsive valve assembly of this invention comprises a two part valve body, the first part having five ports leading into a manifold portion with five separate chamber paths provided therein. The ports and manifold fit into the thermally conductive second body part and are secured therein. Within the second body part is a bimetallic coil which has its outside tang fixed in a bail and its inside end secured in an arbor which is free to rotate as the inside end of the coil rotates in response to temperature change. The rotation of the arbor causes a switch disc which is in sealing contact with the manifold and having prepositioned passages to also rotate causing the new position of these paths to switch control functions from vacuum to vent and back again at the desired temperature. The valve body includes a thermally conductive portion adapted for heat exchange with an object, such as an automobile engine, for transferring heat to or from the coil to increase or decrease the temperature of the coil in response to a corresponding increase or decrease in the temperature of the object.